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Allowance for Credit Losses (Impairment By Loan Class) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	$ 1,975	$ 19,447
Loans Individually Evaluated for Impairment, Allowance	308	279
Loans Collectively Evaluated for Impairment, Recorded Investment	7,385,562	7,522,307
Loans Collectively Evaluated for Impairment, Allowance	107,973	108,780
Commercial, financial and agricultural | Domestic | Commercial
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	567	1,189
Loans Individually Evaluated for Impairment, Allowance	238	209
Loans Collectively Evaluated for Impairment, Recorded Investment	1,706,857	1,784,747
Loans Collectively Evaluated for Impairment, Allowance	22,825	21,699
Commercial, financial and agricultural | Domestic | Commercial Real Estate: Farmland and Commercial
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	404	439
Loans Collectively Evaluated for Impairment, Recorded Investment	2,597,973	2,288,869
Loans Collectively Evaluated for Impairment, Allowance	34,238	30,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate: Multifamily
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	121	134
Loans Collectively Evaluated for Impairment, Recorded Investment	365,246	440,910
Loans Collectively Evaluated for Impairment, Allowance	4,206	5,051
Real estate - construction | Domestic | Commercial Real Estate: other construction and land development
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	769	17,496
Loans Individually Evaluated for Impairment, Allowance	70	70
Loans Collectively Evaluated for Impairment, Recorded Investment	1,617,724	1,829,261
Loans Collectively Evaluated for Impairment, Allowance	33,533	37,542
Real estate - mortgage | Domestic | Residential First Lien
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	79	151
Loans Collectively Evaluated for Impairment, Recorded Investment	399,092	404,968
Loans Collectively Evaluated for Impairment, Allowance	3,916	3,874
Real estate - mortgage | Domestic | Residential Junior Lien
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	35	38
Loans Collectively Evaluated for Impairment, Recorded Investment	516,947	593,987
Loans Collectively Evaluated for Impairment, Allowance	8,196	9,570
Consumer | Domestic
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Collectively Evaluated for Impairment, Recorded Investment	40,505	40,595
Loans Collectively Evaluated for Impairment, Allowance	268	291
Foreign | Foreign
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Collectively Evaluated for Impairment, Recorded Investment	141,218	138,970
Loans Collectively Evaluated for Impairment, Allowance	$ 791	$ 753

X

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524

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- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
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+ References

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-Publisher FASB
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-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
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